1.0Electrical Riddlehttps://electrical-riddle.com/enElectrical Riddlehttps://electrical-riddle.com/enrich600338<blockquote class="wp-embedded-content" data-secret="bxAUcEOtsS"><a href="https://electrical-riddle.com/en/forums/reply/1172/">Reply To: Protection Riddle No.44 – Bad designing of protection circuit and disastrous accident in power plant</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://electrical-riddle.com/en/forums/reply/1172/embed/#?secret=bxAUcEOtsS" width="600" height="338" title="“Reply To: Protection Riddle No.44 – Bad designing of protection circuit and disastrous accident in power plant” — Electrical Riddle" data-secret="bxAUcEOtsS" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script> /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); //# sourceURL=https://electrical-riddle.com/wp-includes/js/wp-embed.min.js </script> The quickest acting trip in order to protect the turbine/generator bearing is best. I’d choose #1. As soon as 27 relay senses the under frequency, according to the diagram it will let the dc travel through it to activate the trip circuit. Depending upon what 27 relay you use, I’d strongly recommend testing this relay … Read More »